Passive electronics components comprising coated nanoparticles and methods for producing and using the same

ABSTRACT

The present invention provides various passive electronic components comprising a layer of coated nanoparticles, and methods for producing and using the same. Some of the passive electronic components of the invention include, but are not limited to conductors, resistors, capacitors, piezoelectronic devices, inductors and transformers.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/973,352, filed Apr. 1, 2014, the disclosure of which is incorporatedherein by reference in its entirety.

FEDERAL FUNDING STATEMENT

This invention was made with government support under Contract No.DE-SC0010239 awarded by the Department of Energy. The Government hascertain rights in this invention.

FIELD OF THE INVENTION

The present invention relates to various passive electronic componentscomprising a layer of coated nanoparticles, and methods for producingand using the same.

BACKGROUND OF THE INVENTION

The incorporation of particles from millimeter-scale down to nanometersin size is ubiquitous in end-use products produced in industrial-scalequantities. A significant percentage of the particles used across allindustries require that the surfaces be coated with a shell, layer,film, or other coating, ranging from sub-nanometer to hundreds ofmicrometers in thickness. For a variety of reasons, each sector orindustry has determined that the incorporation of coated particles intothe end-use product provides enough value, e.g., in the form of enhancedperformance of the product, that the cost associated with each coatingprocess is justified. Energy storage is one application where nanoscalecoatings can significantly improve the uniformity and compatibility ofsurfaces, allowing for preferential transfer of beneficial ions orelectrons across interfaces, while reducing the propensity fordetrimental or corrosion promoting species from degrading or otherwisealtering these interfaces.

The performance of passive electronic components such as capacitortechnologies, including single-layer or multilayered ceramic capacitors(MLCC), electrolytic capacitors, polymer film capacitors, or emergingultracapacitor and/or supercapacitor systems, relies on the quality ofcontrol across interfaces, which in turn defines the specification forcapacitance, dielectric strength, breakdown voltage, dielectric loss,etc. Mechanisms to tailor and optimize all surfaces of all materialscontained within the system leads to better control, definition,functionality or other specification of performance of any feature ofeach system.

Ceramic capacitors (bulk ceramic and MLCCs) have existed for quite sometime, and the state of the art has progressively advanced to higherenergy density, power density, lifetime/durability, and similaradvances, all while occupying a decreasing footprint that trends withsmaller sizes of integrated circuit technologies. Barium titanate(BaTiO₃) is a commonly used dielectric material. Extensive work on thismaterial has demonstrated that tailored bulk content (e.g., dopants,protonation, etc.) or utilization of surface coatings (e.g., Al₂O₃,SiO₂, etc.) can be used to achieve higher breakdown voltages thanuntreated materials. Constantino et al. (U.S. Patent ApplicationPublication No. 2001/0048969) discusses Al₂O₃-coated or SiO₂-coatedsub-micron BaTiO₃ particles that are exemplary of these additionalperformance features. Many other tactics have been used to modifydielectric materials to achieve improved device properties.

Methods of producing compositionally-tailored ceramic/dielectric layersthemselves using additive, layer-by-layer controlled techniques, eventhose as precise as Atomic Layer Epitaxy or Atomic Layer Deposition asdescribed by Suntola et al. (U.S. Pat. No. 4,058,430), have beendeployed to achieve similar effects (see, for example, Ahn, et al., U.S.Patent Application Publication No. 2011/0275163). In addition,techniques that cast or otherwise form a bulk layer consisting of aplurality of compositionally-tailored coated dielectric particles havealso been described. See, for example, Constantino et al. in U.S. PatentApplication Publication No. 2001/0048969. Coating processes forparticles as precise as Atomic Layer Deposition is described by Lakomaa,et al. in the seminal demonstration of ALD coated particles: “Atomiclayer growth of TiO₂ on silica”, Applied Surface Science 60/61 (1992)742-748.

Several years after the seminal publication of conformal metal oxidecoatings on microfine powders (produced using sequential self-limitinggas phase reactions that occurred homogeneously on the surfaces ofparticles in a fixed bed of particles enclosed in a single batchreactor), additional patents have been issued pertaining to ALD andnon-ALD techniques for producing high quality coatings on particles,including nanoparticles. As examples included herein by reference,Krause et al. (EP 0865819) discuss methods of encapsulating particlesusing fluidized beds; Cansell et al. (U.S. Pat. No. 6,592,938) discussmethods of coating particles using organometallic precursors that areindividually known to undergo self-limiting reactions under traditionalALD conditions. Cansell further discusses (see U.S. Pat. No. 7,521,086)as to how the latter coating technique could similarly be utilized forthe production of a metal oxide encapsulated BaTiO₃.

As described by King et al. (US 2011/0236575), vapor depositionprocesses are usually operated batch-wise in reaction vessels such asfluidized bed reactors, rotary reactors and V-blenders, amongst others.Batch processes have significant inefficiencies when operated at largescale. One of the disadvantages of batch processes is that the reactorthroughput is a function of the total particle mass or volume loadedinto a certain sized vessel for a given process, the total process time(up-time), and the total time between processes (down-time) to load,unload, clean, prepare, etc. In addition, batch processes incur largedown-times because at the end of each batch the finished product must beremoved from the reaction equipment and fresh starting materials must becharged to the equipment before the subsequent batch can be produced.Equipment failures and maintenance add to this downtime in batchprocesses.

Moreover, relatively speaking, batch process equipment tends to be verylarge and expensive. The need to operate these processes under vacuumadds greatly to equipment costs, especially as equipment size increases.Because of this, equipment costs for batch processes tend to increasefaster than operating capacity.

Another problem that occurs as the process equipment becomes larger isthat it becomes more difficult to maintain uniform reaction conditionsthroughout the vessel. For example, temperatures can vary considerablywithin a large reaction vessel. It is also difficult to adequatelyfluidize a large mass of particles, specifically nanoparticles. Issuessuch as these can lead to inconsistencies and defects in the coatedproduct.

In vapor deposition processes such as ALD and Molecular Layer Deposition(MLD), the particles are contacted with two or more different reactantsin a sequential manner. This represents yet another problem for a batchoperation. For a traditional batch process, all cycles are performedsequentially in a single reaction vessel. The batch particle ALD processincurs additional down-time due to more frequent periodic cleaningrequirements, and the reaction vessels cannot be used for multiple filmtypes when cross-contamination could be problematic. In addition, thetwo sequential self-limiting reactions may occur at differenttemperatures, requiring heating or cooling of the reactor between cyclesteps in order to accommodate each step.

The throughput for a batch process can be increased either by buildinglarger reaction vessels and/or operating identical reaction vessels inparallel. The capital cost to counteract this down-time from athroughput perspective is to build a larger reaction vessel. With largervessels, localized process conditions, including internal bed heating,pressure gradients, mechanical agitation to break up nanoparticleaggregates, and diffusion limitations amongst others, become moredifficult to control.

Furthermore, there is a practical maximum reaction vessel size whenperforming ALD processes on fine and ultra-fine particles, which limitsthe throughput for a single batch reactor operating continually. Ingeneral, the time duration for the process of producing a given amountof coated materials equals the up-time plus down-time. There is also apractical maximum allowable in capital expense to fabricate anALD-coated particle production facility, which effectively limits thenumber of batch reactors that can operate identical processes inparallel. With these and other constraints, there are practicalthroughput limitations that prohibit the integration of some particleALD processes at the industrial scale.

King et al. (U.S. Patent Application Publication No. 2011/0236575)discusses a high-rate “Spatial ALD” manufacturing process and apparatusfor coating particles in semi-continuous fashion using an array ofisolated vessels with counter-current gas-solids transport. Van Ommen etal. (U.S. Patent Application Publication No. 2012/0009343) discussesanother high-rate “Spatial ALD” process and apparatus to coat particlesin a fully continuous co-current gas-solids transport scheme. Each ofthese methods has its own ascribed operating cost. These methods aresuitable for the manufacture of particular coated particles. Inaddition, each of these methods is believed to be superior andeconomically more viable to traditional batch (or “temporal”) ALDcoating methods. Fotou et al. (Sequential Gas-Phase Formation of Al₂O₃and SiO₂ Layers on Aerosol-Made TiO₂ Particles” Advanced Materials(1997), 9, No. 5, 420-423) discuss methods of producing nanocoatings onsubmicron particles by exposing reactive precursors to the surfaces ofparticles using continuous-flow Chemical Vapor Deposition techniques.However, the consistency, uniformity and thickness do not lendthemselves easily to less than 5 nm coatings on submicron-sizedparticles.

It is expected that a thin film coating (e.g., 5 nm or less) onnanoparticles that are used in passive electronic components willprovide a significant protection from degradation and/or oxidation ofnanoparticles while maintaining substantially all of its electronicfunction.

Accordingly, there is a need for thin film coated nanoparticles andmethods for producing and using the same in passive electroniccomponents.

SUMMARY OF THE INVENTION

Some aspects of the invention provide a passive electronics componentcomprising nanoparticles that are coated with a thin film of material.The thin film coating can be an oxidation-resistant material or areliability-improving material. As used herein, the term“reliability-improving materials” refers to materials that can improvethe performance and/or the life span or mean time to failure of thepassive electronics component compared to the same passive electronicscomponent in the absence of the thin film coating. In one particularinstance, the reliability-improving materials increase the performanceof the passive electronics component by at least 10%, typically by atleast 25%, and often by at least 100%. compared to the same passiveelectronics component in the absence of the thin film coating. Inanother instance, the reliability-improving materials increase the meantime to failure of the passive electronics component by at least 20%,typically by at least 50%, and often by at least 200% relative to thesame passive electronics component in the absence of the thin filmcoating.

As used herein, the terms “same passive electronics component in theabsence of the thin film coating” and “similar passive electronicscomponents in the absence of the thin film coating” are usedinterchangeably herein and refer to the electronics component that isproduced using the same material and same process except for the absenceof the thin film coating.

In one particular aspect of the invention, the passive electronicscomponent comprises an electrode layer of electric conductingnanoparticles. The nanoparticles of the invention are coated with a thinfilm of oxidation-resistant material. The thin film ofoxidation-resistant material prevents oxidation of the nanoparticleswhile maintaining the function of the electrode layer substantially thesame as that of a similar electrode layer of electric conductingnanoparticles in the absence of said thin film of oxidation-resistantmaterial. As used herein, the term “similar electrode layer” refers toan electrode layer that is produced in identical conditions except forthe absence of the thin film of oxidation-resistant material. The term“nanoparticles” refers to particles having average or median particlesize of 1000 nm or less, typically 500 nm or less, often 400 nm or less,and most often 250 nm or less. Alternative, the term “nanoparticles”refers to particles in which 80% or more, typically 90% or more andoften 95% or more of the particles have the particle size of 1000 nm orless, typically 800 nm or less, and often 600 nm or less. As usedherein, the term “thin film” refers to a film or a coating of a materialhaving mean or median thickness of about 20 nm or less, typically 10 nmor less, often 5 nm or less, and most often 3 nm or less. Alternatively,the term “thin film” refers to a film of from about 2 to about 6 nm inthickness. Still alternatively, the term “thin film” refers to amono-atomic or molecular layer of coating material. Often, the term“thin film” refers to the thickness of a coating material achieved usingthe process disclosed in a commonly assigned U.S. patent applicationSer. No. 13/069,452, entitled “Semi-Continuous Vapor Deposition ProcessFor The Manufacture of Coated Particles.” In general, the thin film isformed by an atomic layer deposition process, which can be carried outin a batch mode, semi-continuous mode, continuous mode, or a combinationthereof It should be appreciated that the thin film can also be formedusing any of the methods known to one skilled in the art.

In some embodiments, the thin film of oxidation-resistant materialprovides no significant additional resistivity to said nanoparticles.The term “no significant additional resistivity” refers to a resistivityof a coated nanoparticle, which first has its native oxide removed priorto coating, whose resistivity differs from the resistivity of uncoatednanoparticle of same composition, without the native oxide beingremoved, by no more than about 20%, typically no more than about 10%,and often no more than about 5%.

Yet in other embodiments, the thin film of oxidation-resistant materialdoes not significantly affect the sintering of said nanoparticles. Asused herein, the term “sintering” refers to atomistic diffusion betweennanoparticle and the thin film or atomistic diffusion betweennanoparticles. Also as used herein, the term “does not significantlyaffect the sintering of said nanoparticles” means the amount ofsintering or the sintering temperature in the presence of the thin filmcoating is substantially similar to the amount of sintering or thesintering temperature of the same nanoparticles in the absence of a thinfilm coating. Generally, the amount of nanoparticle sintering in thepresence of the thin film coating is no more than 15%, typically no morethan 10%, and often no more than 5% different compared to the amount ofnanoparticle sintering in the absence of the thin film coating.Alternatively, the sintering temperature in the presence of the thinfilm coating is within 50° C., typically within 30° C., and often within20° C. of the nanoparticle sintering temperature in the absence of thethin film coating.

Still in other embodiments, the thin film of oxidation-resistantmaterial comprises a thin film of wide bandgap material. As used herein,the term “wide bandgap material” refers to materials with electronicband gaps significantly larger than 1.5 electron volt (eV), typicallylarger than 3.0 eV, and often larger than 5.0 eV. In some instances, thewide bandgap material comprises a material selected from the groupconsisting of aluminum oxide, hafnium oxide, zirconium oxide, tantalumoxide, niobium oxide, lithium oxide, silicon oxide, calcium oxide,magnesium oxide, boron oxide, aluminum phosphate, titanium phosphate,lithium phosphate, calcium phosphate, aluminum nitride, gallium nitride,boron nitride, boron carbide, and a combination thereof Still in otherinstances, the thickness of the thin film coating of wide bandgapmaterial is 8 nm or less, typically 5.5 nm or less, and often 3.5 nm orless.

In other embodiments, the thin film of oxidation-resistant materialcomprises a thin film of semiconducting or conducting material.Exemplary semiconducting materials that are suitable for the presentinvention include, but are not limited to, zinc oxide, titanium oxide,cerium oxide, vanadium oxide, barium oxide, bismuth oxide, rutheniumoxide, indium oxide, tin oxide, lanthanum oxide, titanium nitride,tantalum nitride, silicon carbide, and ternary or quaternarycombinations that include these and other analogous materials. Exemplaryconducting materials that are useful in the present invention include,but are not limited to, metals (such as platinum, silver, gold,titanium, copper, zinc, chromium, nickel, iron, molybdenum, tungsten,ruthenium, palladium, indium, and tin), alloys or intermetallics (suchas PtNi, FeCrAlY, AgPd, nichrome, and other conductive steels) and otherelectric conducting materials such as those containing carbons (such asgraphite, graphene, diamond and diamond like carbon, and PEDOT and otherconductive polymers).

In one particular embodiment, the resistivity of said thin film ofoxidation-resistant material is 50,000 μΩ-cm or less, typically 5,000μΩ-cm or less, and often 500 μΩ-cm or less.

Yet in other embodiments, the thin film of oxidation-resistant materialcomprises a dopant material. Exemplary dopant materials that are usefulin the invention include, but are not limited to, +5 valence materialsinto +4 valence materials (such as tantalum oxide doped into titaniumoxide), +3 valence materials into +2 valence materials (such as aluminumoxide doped into zinc oxide), and commonly known doped transparentconductive oxides (such as fluorine-doped tin oxide). Typically, thedopant material increases the conductivity of the thin film ofoxidation-resistant material by at least 20%, often by at least 50% andmost often by at least 100%.

Still in other embodiments, a thermal oxidation onset temperature of thenanoparticles with the thin film coating is at least 10° C., typicallyat least 25° C., and often at least 100° C. higher than the samenanoparticles in the absence of said thin film of oxidation-resistantmaterial.

Yet still in other embodiments, the average particle size of saidnanoparticles is 1,000 nm or less, typically 800 nm or less, and often500 nm or less.

Depending on a particular application, the passive electronics componentcan comprise a plurality of said electrode layers.

Another aspect of the invention provides a passive electronics componentcomprising a dielectric or piezoelectric layer of correspondingnanoparticles that are coated with a thin film of areliability-improving material. In this aspect of the invention, thenanoparticles are dielectric or piezoelectric nanoparticles. Exemplarydielectric or piezoelectric materials that are useful in the presentinvention include nanoparticles composed of materials including, but arenot limited to, barium titanate, strontium titanate, barium strontiumtitanate, barium niobate, strontium niobate, barium strontium niobate,sodium niobate, potassium niobate, sodium potassium niobate, titania,zirconia, lead zirconate, lead zirconate titanate, calcium coppertitanate, bismuth scandium oxide, bismuth zinc oxide, bismuth titanate,bismuth zinc titanate, zinc oxide, and zinc titanate.

In some embodiments, the reliability-improving material comprises SiO₂,ZrO₂, B₂O₃, Bi₂O₃, Li₂O, or a mixture thereof.

Still in other embodiment, the thin film coating reduces thedensification onset temperature of said nanoparticles. As used herein,the term “densification” means atomistic diffusion between or within thethin films, and/or interactions with additional densification aids (suchas glass or glass-forming powders) present in the system, as relevant.Also as used herein, the “densification onset temperature” means thetemperature at which nanoparticles coated with thin films begin todensify and reduce the void space present between a plurality of saidnanoparticles. The densification temperature of nanoparticles in theabsence of a thin film coating is the same as the sintering temperatureof the nanoparticles. Alternatively, the thin film coating serves as asolid precursor to liquid phase sintering of the nanoparticles, attemperatures substantially lower than the traditional sinteringtemperature of said nanoparticles. In general, the densificationtemperature of the nanoparticles is at least 25° C. lower, typically byat least 50° C. lower, and often by at least 100° C. lower than thesintering temperature of the same nanoparticles in the absence of thethin film coating.

In one particular embodiment, said nanoparticles comprise bariumtitanate, and said reliability-improving material comprises an oxide ofa metal comprising bismuth, zinc, titanium, scandium, or a mixturethereof In some instances within this embodiment, saidreliability-improving material comprises zinc titanium oxide, bismuthzinc titanium oxide or bismuth scandium oxide.

In another embodiment, said nanoparticles comprise an alkali niobateperovskite, and said reliability-improving material comprises an oxideof a metal selected from the group consisting of tantalum, sodium,potassium, or a mixture thereof In some instances within thisembodiment, said reliability-improving material comprises an alkalitantalate.

Yet in another particular embodiment, said reliability-improvingmaterial increases the mean time to failure by at least 10% relative tothe same passive electronics component in the absence of said thin filmof reliability-improving material.

Still in another particular embodiment, said thin film ofreliability-improving material reduces the average grain size of saidnanoparticles by at least 20 nm, typically by at least 50 nm, and oftenby at least 100 nm when fired into fully-dense parts.

As stated above, the thin film coating in some embodiments is producedat least in part using an atomic layer deposition or molecular layerdeposition process.

The scope of the invention also includes a passive electronics componentcomprising a plurality of said dielectric or piezoelectric layers.

Still another aspect of the invention provides a passive electronicscomponent comprising a dielectric and/or piezoelectric layer describedherein in combination with an electrode layer comprising electricconducting nanoparticles described herein. That is said nanoparticles ofsaid dielectric and/or piezoelectric layer are coated with a thin filmof a reliability-improving material and/or said electric conductingnanoparticles are coated with a thin film of oxidation-resistantmaterial.

Other aspects of the invention include an electronic device comprising apassive electronics component disclosed herein such as one or moreelectrode layer(s), dielectric layer(s), and/or piezoelectric layer(s).

One specific aspect of the invention provides a capacitor comprising athin film coated nanoparticles, wherein said thin film coatednanoparticles comprise an electric conducting nanoparticles that arecoated with a thin film of an oxidation-resistant material, and whereinsaid thin film prevents oxidation and sintering of but substantiallymaintains the electric conductivity property of said nanoparticles. Insome embodiments, said oxidation-resistant material comprises a widebandgap material. In some embodiments, said capacitor is a multilayeredceramic capacitor or MLCC.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1—A transmission electron microscope (TEM) image of an exemplaryset of coated electrode-grade nickel nanoparticles with limited (˜5-10%)agglomeration. Particles ranged from ˜50 nm to ˜600 nm in this sample.

FIG. 2—A magnified TEM image of the lower left portion of FIG. 1,showing coated particles that had agglomerated during the ALD coatingprocess using a batch fluidized bed reactor.

FIG. 3—A magnified TEM image from the upper right portion of FIG. 1,showing coated particles that have necked together during the ALDcoating process using a batch fluidized bed reactor.

FIG. 4—A high resolution TEM image of an exemplary ˜7 nm coating on anelectrode-grade nickel nanoparticle.

FIG. 5—Thermal gravimetric analysis (TGA) thermal stability testing ofuncoated and coated electrode-grade nickel nanoparticles in air. Theweight was measured continuously while the temperature was increased ata 10° C./min rate. The uncoated material began to increase in weight,which is indicative of the onset of nickel oxidation, at 300° C.; thecoated material began to increase in weight at 700° C.

FIG. 6—Thermal stability testing of uncoated and coated electrode-gradenickel nanoparticles at 300° C. for 12 hours, designed to mimic a binderburn-out process in air. The uncoated nickel nanopowder originally had0.1% NiO by weight, and oxidized to 16.6% NiO after the 12 hour dwellperiod. A sub-critical ALD coating thickness was used for the test, andreduced the amount of oxidation to 10.5%. The optimal coating thicknessidentified, which was twice as thick as the sub-critical ALD coatingthickness, effectively prevented all oxidation while allowing a binderburn-out process to occur at 300° C. in air rather than a conventionaltemperature of 270° C. in air.

FIG. 7—Dielectric constant and loss (tan delta) measurements for alkaliniobate—nickel nanopowder co-fired capacitors produced with uncoated andcoated nickel nanopowder over a range of co-firing oxygen partialpressures. Nearly independent of oxygen partial pressures, the thin filmcoated nickel nanoparticles demonstrated ability for repeatabledielectric constant with ultra-low dielectric loss, without modifyingthe dielectric powders themselves. This invention can ultimately allowfor fast co-firing steps to be carried out in air, and allow thin filmcoated nickel or copper nanoparticles to supplant platinum andsilver-palladium used in air firing steps today. This test also showedthat even in samples with limited agglomeration due to the coatingprocess, the performance of mildly agglomerated thin film coated nickelnanoparticles remains suitable for electrode applications.

FIG. 8—Dielectric constant and loss (tan delta) measurements for alkaliniobate—nickel nanopowder co-fired capacitors produced with uncoated andcoated nickel nanopowder over a range of co-firing oxygen partialpressures; raw data from FIG. 7.

FIG. 9—Comparison of XRD data for Ni and NiO for coated and uncoated NiPowders Fired in Air in an Elevator Kiln showing negligible NiO in theALD coated case. Images of Nickel ink samples after firing@800° C./3 min(inset) are shown, with the outline color matching the colors on the XRDspectra legend. This data suggests that ALD coatings are much morerobust to thermal shock than originally anticipated. Those skilled inthe art have attributed the oxidation of nanocoated metal powders tofilm cracking allowing oxygen ingress, when viewing TGA data shown inFIG. 5 at a temperature ramp rate of 10° C./min; however an unexpectedlygreater thermal stability has been demonstrated for this ˜250° C./minthermal shock. The cooling time was substantial enough that the materialremained above 300° C. for long enough that additional oxidation wouldhave been rampant for grossly cracked films, and this was not the case.

DETAILED DESCRIPTION OF THE INVENTION

Electronic devices have become ubiquitous in today's society. As modernelectronic devices have become smaller, their components have alsobecome smaller. In fact, some components of modern electronic devicesare micro-scales. As these electronic components become smaller, theyare more susceptible to degradation or oxidation, which significantlyreduces the life of modern electronic devices. Electronic devicescontain both active and passive electronic components. The term “passiveelectronic components” refers to components of electronic devices thatcan't introduce net energy into the circuit. Exemplary passiveelectronic components include, but are not limited to, two-terminalcomponents such as resistors, capacitors, inductors, and transformers.In general, passive electronic components can't rely on a source ofpower, except for what is typically available from the circuit they areconnected to. Thus, passive electronic components can't amplify (e.g.,increase the power of a signal), but they may increase a voltage orcurrent (e.g., as is done by a transformer or resonant circuit).

While present invention relates to a thin film coated nanoparticles thatare used in various passive electronic components, for the sake ofbrevity and clarity the present invention will now be described inreference to capacitors. However, it should be appreciated that thescope of the invention includes thin film coated nanoparticles that areused in other passive electronic components such as resistors,inductors, and transformers. Moreover, methods disclosed herein can beused to produce such other passive electronic components.

Today, MLCCs are most efficiently manufactured through the casting ofalternating layers of inks/pastes consisting of electrode powders anddielectric powders, stacked in direct contact with one another, andafter which binder burn-out and co-firing (e.g., sintering) steps areexecuted on assembled systems. Exemplary processing techniques aredescribed by Imanaka (“Multilayered Low Temperature Co-fired CeramicsTechnology”, Springer, 2005) and by Nakano et al. (U.S. Pat. No.7,595,974), which are incorporated herein by reference in theirentirety.

There is an industry need to supplant the use of silver, platinum,palladium, and other costly precious metals used in electrodeinks/pastes with base metals having one or more protective oxidationbarrier coatings. Adopting suitable methods of supplanting expensivematerials for low-cost base metals that achieve the same level ofapplication functionality will significantly reduce the cost of MLCCsand other advanced power electronics devices. Hakim et al. (“Synthesisof oxidation-resistant metal nanoparticles via atomic layer deposition”Nanotechnology 29 (2007) 345603-345609) discusses how ALD can be used toencapsulate base metal particles, and extend their oxidation onsettemperature by hundreds of degrees Celsius. Furthermore, ultrafine basemetal powders can be produced via metal oxalate decomposition asdescribed by Dunmead et al. (U.S. Pat. No. 6,689,191). Those skilled inthe art have claimed that the oxidation onset temperature is driven byfilm cracking, however the present thin film coated nanoparticles can bethermally treated above this oxidation onset temperature duringfast-firing steps without substantial oxidation as would be anticipatedfrom films that crack at the oxidation onset temperature as measuredusing slow heating rates.

It is unexpected, however, that when producing insulator-coatedelectrode powders using ALD, that these composite particles (e.g.,BaTiO₃—Ni MLCCs with co-fired inner electrodes) can function as well aspristine base metal electrode powders used today. Especially in light ofU.S. Pat. No. 7,132,697, issued to Weimer et al. (the “Weimer et al.Patent”), discussing that ALD coated metal particles of 10 nm to 500 μmin diameter, with insulating coatings of 0.25 nm-500 nm in thickness,demonstrated non-linear resistivity with respect to film thickness. Thispatent implicitly appears to teach that metal particles coated withinsulating metal oxide coatings deposited using ALD cannot serve as adrop-in replacement to uncoated particles in many other passivecomponent applications such as capacitors and conductors.

In contrast to these teachings, the present inventors have discoveredthat the incorporation of 2-5 nm Al₂O₃ ALD coated submicron metallic Niparticles (600 nm and smaller) results in no significant additionalresistivity even when operating at voltages below the accepted breakdownstrength of bulk aluminum oxide. In some embodiments, metallic nickelparticles are subjected to native oxide removal pretreatments prior tocoating. The resulting ALD-coated metallic nickel particles can be usedto either fully or partially supplant uncoated Ni particles (or thecorresponding Ag, Pt and other common electrode materials). Similarly,ALD-coated metallic copper particles can be used to either fully orpartially supplant uncoated Cu particles (or the corresponding Ag, Ptand other common electrode materials). Accordingly, some aspects of theinvention provide a single-layer ceramic capacitor and/or MLCCs thatyields no significant additional resistivity due to the coatingsrelative to the base metal itself As used herein, the term “nosignificant additional resistivity” refers to a resistivity of anALD-coated base metal nanoparticle, which first has its native oxideremoved prior to coating, whose resistivity differs from the resistivityof uncoated base metal nanoparticle of same composition with its nativeoxide intact, by no more than about 20%, typically no more than about10%, and often no more than about 5%. In some embodiments, the thin filmof oxidation-resistant material provides no significant additionalresistivity to said nanoparticles. Moreover, it has been discovered bythe present inventors that a wide variety of nanoparticles that can beused in passive electronic components can be coated with a thin film ofprotective material. As used herein, the term “nanoparticles” refers toparticles having average or median particle size of 1,000 nm or less,typically 500 nm or less, often 400 nm or less, and most often 250 nm orless. Alternative, the term “nanoparticles” refers to particles in which80% or more, typically 90% or more and often 95% or more of theparticles have the particle size of 1,000 nm or less, typically 800 nmor less, and often 600 nm or less. As used herein, the term “thin film”refers to a film or a coating of a material having mean or medianthickness of about 20 nm or less, typically 10 nm or less, often 5 nm orless, and most often 3 nm or less. The term “base material” refers tothe core material or nanoparticles of the invention. The term “coating”or “shell” is sometimes used to describe a thin film of material thatcovers the nanoparticles or the core material. It should be appreciatedthat the nanoparticle material and the thin film of coating aretypically composed of different materials.

Surprisingly and unexpectedly, the present inventors have discoveredthat applying a conductive ALD coating (or a semiconducting coating withan electronic band gap that is less than the operating voltage) to thesurface of a 3,000 nm base metal electrode powder (copper) that hadnative oxide remaining intact, resulted in non-conductive compositeparticles. This observed result is contrary to what is disclosed orimplied in the Weimer et al. Patent, which describes “a non-conductivecoating that is deposited on core conductive particles using atomiclayer deposition methods.” For example, one of the examples in theWeimer et al. Patent describes 5,000 nm diameter iron particles coatedwith 5.5 and 22 nm Al₂O₃ films. The Weimer et al. Patent also identifiedthe presence of an Fe₂O₃ native oxide interlayer (a commonly knowninsulator) at the interface between the innermost surface of the coatingand the outermost surface of the core particle. Elsewhere, Weimer et al.have published that 7.5 nm-22 nm coatings on micron-sized Nickel powderdemonstrated a similar nonlinear resistivity to the coated irondescribed in the Weimer et al. Patent. See, “Ultrafast metal-insulatorvaristors based on tunable Al₂O₃ tunnel junctions” Applied PhysicsLetters 92, (2008) 164101. However, no mention was made in this work asto whether the native oxide remained intact at the surface or ifpretreatment steps were utilized to remove the native oxide. The Weimeret al. Patent implies that the insulating Al₂O₃ coating is the exclusivefeature of their invention that provides non-linear resistivity withfilm thickness, while neglecting the contribution of the native oxide,which is also commonly known to be an insulator. There is an implicitpresumption that the uncoated core conductive particles used for thestudy were tested in the same manner as the coated particles, however nodata is presented for the 5,000 nm diameter iron particles with a nativeFe₂O₃ layer, nor is any particle size smaller than 5,000 nm described.More importantly, it is well known to those skilled in the art ofproducing electronic components from powdered materials or inkscontaining powdered materials that there is a strong non-linearresistivity with respect to pressure. The Weimer et al. Patent does notdiscuss pressure; the publication however offers that the materials wereplaced in a centrifuge, and it is implicitly understood to be subject toa very high compaction pressure. This matrix of particles produced andtested is entirely different from how conventional passive electronicscomponents such as conductors and capacitors are produced, specificallyusing an electrode layer produced through the printing of aparticle-containing ink. Most surprisingly to the inventors was thediscovery that conductive particles of 1,000 nm and smaller, firsthaving the native oxide removed, and second having a coating process inwhich a thin (typically 2-6 nm) insulating ALD film was applied, wasparticularly useful as a conductive electrode powder for passiveelectronics components consisting of layers of electrode powdersproduced using conventional ink printing technologies, and moreover thatthese materials could be drop-in replacements for conductive electrodepowders that did not have a thin film coating.

One difficulty faced when dealing with fine metal powders, especiallysubmicron powders, is their propensity to form native oxide films in thepresence of air and moisture, even at standard temperatures andpressures. For example, in the examples discussed above by Weimer etal., ALD-coated 5 micron metallic iron particles showed the presence ofiron oxide at the interface between the particle and coating. It is wellknown to one skilled in the art that steps to remove this native oxideprior to coating can significantly improve the quality of the coatedmetal powders and their suitability for use in particular applications.Processes for removing native oxides are well known to one skilled inthe art. For example, gas-solid contacting steps, in which metalparticles are exposed to reducing gases at elevated temperatures, areoftentimes suitable in reducing the oxidation state of core materials,promoting oxygen vacancies, and/or promoting other beneficial phenomena.Similar reducing gas (e.g., “forming gas”) exposures (sometimes referredto as protonation pretreatment steps) have been successful in improvingproperties of dielectric materials such as BaTiO₃. As is the case withpristine (i.e., substantially pure or a purity of at least 95%,typically at least 98% often at least 99%, and more of the at least99.5%) metals that have higher surface energy than their native oxidecoated counterparts, there is a strong likelihood that ultrafinemetallic particles will permanently sinter or otherwise agglomerate ifadjacent particles with reduced surfaces are allowed to come in contactwith one another for extended periods of time during reduction steps inelevated temperature. Coatings have proven to be useful in preventinginter-particle sintering. In general, coating can prevent sinteringentirely compared to uncoated particles that undergo sintering undersimilar conditions. In some instances, coating allowed a significantreduction in sintering as evidenced by requiring prolonged time and/orsintering temperature. In some cases, coating a particle increasedsintering temperature as much as 200° C. to 300° C. compared to uncoatedparticles under similar conditions.

Some aspects of the invention, therefore, provide a metallic particlecomprising a continuous nanoscale coated oxidation-resistant andelectric conducting film. In some embodiments, the coating is anultrathin coating consisting of a single to a plurality of atomic layercoatings. In one particular embodiment, the coating is an aluminum oxidecoating. The particle size of the metallic particle, prior to coating,is typically from about 50 nm to about 3,000 nm, often from about 80 nmto about 1,000 nm, and most often from about 100 nm to about 600 nm.Typically, the “base material” comprises nanoparticles.

As stated above, compositions of the invention can be used in a widevariety of passive electronic components including in conductors,transducers, actuators, piezoelectrics, transistors, thyristors, andcapacitors. Methods and compositions of the invention can also be usedin conductor-coated metals as core-shell electrode powders. Providing acoating of thin film as described herein provides a wide variety ofbeneficial effects including, but not limited to, limiting agglomerationduring coating process and still achieve results, i.e., maintainsubstantially the similar electric conductivity and/or resistivity.Molecular layer deposition (MLD) process coated particles generally canbe calcined to allow the coating shells to become porous and allow forforming-gas reduction of metals while preventing metals from sintering,i.e., enabling native oxide removal without sintering. An exemplary MLDprocess includes the in situ production of these materials by coatingMLD films on metal oxalate particles, then decomposing the metal oxalateand making MLD porous in single process. Methods of the invention can beused to also produce core-shell magnetic materials, i.e., magneticnanoparticles that are coated with a thin film of non-magnetic “shell”.

Compositions of the invention can also be used to produce improvedelectrode layers by printing, spraying or other means to achieveultrathin layers for MLCCs, single-layer capacitors, batteries,ultra-capacitors, etc. As used herein, the term “improved” refers tohaving increased life-time of the passive electronic components due tothe coating of thin film on nanoparticles. Typically, the life-time ofan electrode layer comprising a thin film coated nanoparticles is atleast 10% more, typically at least 25% more, and often at least 50%more, compared to an electrode layer with the similar (i.e., uncoated)nanoparticles.

Some compositions of the invention include ceramic-coated dielectricparticles. Typically, the atomic layer deposition (ALD) process is usedto produce core-shell dielectrics. As used herein, unless the contextrequires otherwise the term “core” refers to the nanoparticles and theterm “shell” refers to the thin film coating on the nanoparticles. Insome cases, the presence of thin film coating improves or prevents ionmobility in dielectric nanoparticles. In other instances, the thin filmcoating can be used to manipulate or affect the final particle size,e.g., after firing or heating.

A thin film coating present on the nanoparticles of the inventionprevents sintering at high temperature, e.g., during forming gasreduction process. In some cases, the thin film coating, e.g., SiO₂coating, is thin enough to be permeable to reducing gas such as hydrogenwhile preventing sintering of nanoparticles. In some instances,compositions of the invention include MLD-coated particles where thethin film coatings become porous ceramic oxides to allow gas flow. Insuch instances, a second coating of thin film can be applied, e.g.,after heat treatment. In other instances, the second coating of thinfilm provides an impermeable dielectric layer.

The thin film of coating can be applied to nanoparticles using a batchprocess (see the Weimer et al. Patent), a semi-continuous process (seecommonly assigned U.S. patent application Ser. No. 13/069,452, entitled“Semi-Continuous Vapor Deposition Process For The Manufacture of CoatedParticles”), a continuous process (U.S. Patent Application PublicationNo. 20120009343), as well as variations thereof includingplasma-enhanced processes, or a combination thereof

Additional objects, advantages, and novel features of this inventionwill become apparent to those skilled in the art upon examination of thefollowing examples thereof, which are not intended to be limiting. Inthe Examples, procedures that are constructively reduced to practice aredescribed in the present tense, and procedures that have been carriedout in the laboratory are set forth in the past tense.

EXAMPLES

Metallic copper particles devoid of native copper oxide coating, withand without ALD encapsulation coatings, have been produced in a set ofsix trials, using two different copper substrates to compare andcontrast coating processes: two trials utilized 1-5 micron copperpowders that maintained a nanoscale native oxide of copper in theas-received state (substrate A); and two trials utilized thedecomposition of a copper oxalate powder in a fluidized bed reactor(substrate B). For substrates A and B, the following processes were run:

-   -   (1) Forming gas exposure at elevated temperature (450° C.) for        60 minutes;    -   (2) The process of (1) followed by a 3 nm ALD coating of Al₂O₃;        and    -   (3) A first coating of a 5 nm aluminum alkoxide layer via the        Molecular Layer

Deposition (MLD), which results in a mesoporous Al₂O₃ coating during anelevated temperature organic burn-out step. Subsequently the process of(2) was followed, inclusive of the process of (1) as described above.

For cases A-1 and B-1, particle size distributions were shifted todramatically larger values, a clear indication that inter-particlesintering was rampant. The d50 particle size using the B substrate istypically smaller than the d50 particle size of a bulk micron-scalepowder of the same metal. After being exposed to air for 24 hours,copper oxide was clearly observed using XRD. For cases A-2 and B-2, asimilar shift in particle size occurred, as that aspect of theprocessing was identical, however the Al₂O₃ coatings prevented theoxidation of the underlying copper powders as copper oxide was notobserved using XRD. For cases A-3 and B-3, the aluminum alkoxideconverts to a porous Al₂O₃ shell during the forming gas treatment step,which allows for forming gas to directly contact the surface of theparticles, and the reduction step can proceed to completion while onlythe outermost Al₂O₃ surfaces are in contact with one another within theparticle bed. Upon completion of the forming gas reduction step, theAl₂O₃ ALD shell was applied. The 3 nm Al₂O₃ ALD coating was againsufficient to prevent the oxidation of copper particles upon exposure toair for 24 hours. The dramatic difference between A-3 and B-3, relativeto the analogues seeing only processes 1 and 2, was that the particlesize remained largely unchanged, aside from what is naturally expectedwhen carrying out such intensive, sequential coating processes onparticles in vacuum fluidized bed reactors with vastly differenttemperature processing steps.

Barium titanate particles with and without ALD coatings were subject toprotonation steps, or high temperature forming gas exposures. Uncoatedbarium titanate treated for 1 hour at 900° C. in forming gas (4% H₂ inN₂), produced a locally-sintered powder with particle size distributionshifted to significantly larger sizes. Al₂O₃ and SiO₂ ALD coatings wereapplied to pristine barium titanate particles as well, and in both casesafter identical forming gas treatments, the nanoscale coatings weresufficient to prevent sintering-induced aggregation observed extensivelywith the uncoated materials. The Al₂O₃-coated barium titanate turned adeep blue color, perhaps evidence that aluminum doping and/or bariumaluminate formation occurred. However with the glassy SiO₂ coating, thematerial turned dark gray only, while maintaining a uniform particlesize distribution that was changed only due to the fluidized bed coatingprocess itself This set of coating trials elucidated the value oftailoring the sintering prevention coating for specific processes, inthat hydrogen gas in the forming gas process could much more readilydiffuse through the deposited SiO₂ ALD coatings than the deposited Al₂O₃ALD coatings, while the effect of sintering prevention was maintainedindependent of these coating materials. The protonated SiO₂-coatedbarium titanate can then be overcoated using protective Al₂O₃ layers fora grain boundary barrier effect, additional SiO₂, Li₂O or B₂O₃, layersto serve as fritting material, or other coatings depending on thedesired purpose.

ALD-coated submicron-sized nickel powders have been formulated intostandard inks for producing MLCC inner electrode tapes, alongside tapesmade from inks formulated using uncoated nickel powders. Prior to thisformulation, it is advantageous to better understand and define theminimum critical coating thickness required to prevent base metaloxidation during the binder burnout process. This process is typicallyrun at no higher than 270° C. for 12 hours in air; however it is highlydesirable to increase the working temperature to 300° C. for 12 hours inair to reduce the residual carbon and impurities that are normally leftbehind after an incomplete binder burnout process at lower temperatures.The Ni and NiO content was measured on raw powders before and after thisthermal treatment step in a standard tube furnace. The control sampleprior to the binder burnout process had a NiO content of 0.1 wt % asmeasured using powder XRD. The heat treated control sample had aresulting NiO content of 16.6%; one heat treated ALD-coated sample thatwas coated below the critical thickness had a resulting NiO content of10.5%. Thicker ALD-coated samples at or above the critical thickness hadresulting NiO contents of 0.2% or 0.1%.

The alkali niobate/nickel co-fired MLCC system is one of a select numberof possible candidates for lead-free high temperature, high voltage,high reliability capacitors for high temperature power electronics(e.g., SiC-based ICs) that require 150° C.-300° C. device operation.Another such candidate is bismuth zinc titanate-barium titanate (BZT-BT)dielectric layers ideally paired with oxidation-resistant copper innerelectrodes. MLCCs consisting of layers of coated (at the definedcritical thickness) vs. uncoated inner (nickel) electrode tapes andtapes made from formulated pristine alkali niobate powders were eachfabricated to test the hypothesis that passivated base metal electrodescould be used as drop-in replacements to pristine nickel powders forMLCC applications. Post binder burnout, it is common to vary the oxygenpartial pressure during high temperature co-firing steps and measure thedielectric constant and dielectric loss (tan δ) of the system tooptimize the co-firing process for any new materials. For a given casttape thickness, the optimal results would be a controllable dielectricconstant for the layer, and minimal loss.

Processes and procedures to modify or tailor the dielectric materials inthe dielectric layer have demonstrated control over these variables, sothe anticipated result of utilizing passivated Ni tapes relative topristine tapes was that the dielectric properties of the system would beunchanged, but perhaps a higher voltage bias would be needed to utilizethe capacitor devices if the teachings of nonlinear resistivity byWeimer et al. were accurate in submicron base metals and sub 5 nmcoating thicknesses. Two unexpected results were demonstrated by thistest. First, the use of passivated inner electrodes did not requirealtering the electrical test conditions, likely suggesting thatparticles smaller than 1 micron in diameter and/or films thinner than 5nm may not have been produced and evaluated by Weimer. Second, the useof ALD-coated inner electrode materials delivered a significant degreeof robustness to the entire system with respect to a highly uniform andconsistent dielectric constant with respect to co-firing oxygen partialpressure, and an incredibly low dielectric loss. This is the firstdemonstration of coated inner electrode materials paired with pristinedielectric materials that has delivered some of the same benefits asmodifications to the dielectric materials themselves. The implicationsof this are broad and far-reaching, in that not only can ALD-coatedinner electrodes be used to withstand operating conditions of nextgeneration high temperature integrated circuit devices, but thatrelatively simple and low-cost metal coating steps can supplant theextensive and oftentimes complicated dielectric modification stepsdescribed herein. In addition, with better control over the dielectricproperties of individual layers, the practical number of layers withinALD-incorporated MLCCs should be significantly larger than without usingALD-coated materials. This has a direct impact on the energy densityattainable in MLCC devices.

The alkali niobate/nickel co-fired MLCC system was tested using tinoxide coated Ni to determine whether an insulator-metal compositeparticle was critical to affecting the dielectric properties of thesystem, or if a conductive coating could yield the same unexpectedresults. Other materials have also been coated on Ni, such as SiO₂,B₂O₃, TiO₂, Ta₂O₅, Si₃N₄, TiN and other metal oxides and nitridescommonly known to be applied using ALD techniques.

In order to further optimize the systems toward high temperaturelead-free capacitors for demanding applications (e.g., DC Linkcapacitors), the previously described BZT-BT/Nickel and BZT-BT/Copperco-fired MLCC systems were tested with coated and uncoated electrodepowders, and some variants included coatings and/or pretreatments to thedielectric materials themselves. Glassy coatings including SiO₂ and B₂O₃may also be useful to improving the overall homogeneity of theseco-fired systems.

Standard barium titanate/Ni co-fired MLCC systems were also tested withcoated and uncoated electrode powders, and some variants includedcoatings and/or pretreatments to the dielectric materials themselves.Glassy coatings including SiO₂ and B₂O₃ may also be useful to improvingthe overall homogeneity of these co-fired systems as well.

Plasma-enhanced atomic layer deposition (PE-ALD) coating techniques arecommonly used to remove residual contaminants from incomplete surfacereactions at lower operating temperatures. A PE-ALD TiN coated Nielectrode tape was produced along with a conventionally produced ALD TiNcoated Ni electrode tape, to determine whether a change in residualcontaminant (typically Cl from TiCl₄) level results in a higherelectrical conductivity in a particle system, and whether this wouldaffect the dielectric constant and loss to as great of a degree as aninsulative coating or a less conductive coating. An exemplarydemonstration is the production of TiN ALD coatings on particles, inwhich TiCl₄ and NH₃ can be administered in sequential fashion with HClbeing the reaction product. Even at 400° C., there can be residualchlorine in the coatings, which makes the coatings materially differentfrom TiN coatings devoid of contaminants. The TiN process for coatingparticles is identical to that demonstrated by Lakomaa in 1992 for TiO₂(see “Atomic layer growth of TiO₂ on silica”, Applied Surface Science60/61 (1992) 742-748), except NH₃ replaces H₂O in sequentialself-limiting gas-solid contacting steps on particle surfaces in the bedof powder. Low temperature ALD processes using TiCl₄ and H₂O can leave2.0-10.0 wt % chlorine in the films. More recently, Elam et al.(“Surface chemistry and film growth during TiN atomic layer depositionusing TDMAT and NH₃” Thin Solid Films 436 (2003) 145-156) disclosed aroute to TiN ALD using tetrakis-dimethylamino titanium and ammonia, andeven this precursor resulted in 2-5 wt % carbon in the film. The bestfilms possessed a resistivity more than 600 times that of bulk TiN,which is unappealing for most conductive coating applications. TiN viathermal ALD typically has resistivity values>10,000 μΩ-cm, whereasPlasma-Enhanced TiN ALD typically has resistivity values<300 μΩ-cm.PE-ALD was used to deposit TiN onto Ni powders, which are then used asinner electrodes in MLCCs.

The surprising and unexpected discovery of the effect that co-firedALD-coated inner electrodes have on MLCC devices is especially useful ifthe materials can be coated economically and at industrially-relevantrates. The submicron-sized Ni power described earlier was loaded into asemi-continuous ALD reactor as described by commonly assigned U.S.Patent Application Publication No. 2011/0236575, and passed through thesystem at high rates to determine the feasibility of mass production.The core material was passed through the semi-continuous counter-currentflow system for the appropriate number of times to achieve thepreviously defined critical coating thickness for the material. Theoxidation resistance of this material was identical to that produced inlab-scale fluidized bed reactors, however the throughput in thesemi-continuous ALD reactor is ˜200 times the throughput of batchsystems, yet maintains a nearly equivalent footprint. These tests atboth the small scale and large scale demonstrate the applicability ofproducing the composite materials in a large scale, and the ability toincorporate these compositions into conventional and high temperatureMLCC devices, and applicability to a wide array of electronic componentsand devices that are fabricated using inks, pastes or tapes that includeoxidation- resistant base metal electrode powders.

The foregoing discussion of the invention has been presented forpurposes of illustration and description. The foregoing is not intendedto limit the invention to the form or forms disclosed herein. Althoughthe description of the invention has included description of one or moreembodiments and certain variations and modifications, other variationsand modifications are within the scope of the invention, e.g., as may bewithin the skill and knowledge of those in the art, after understandingthe present disclosure. It is intended to obtain rights which includealternative embodiments to the extent permitted, including alternate,interchangeable and/or equivalent structures, functions, ranges or stepsto those claimed, whether or not such alternate, interchangeable and/orequivalent structures, functions, ranges or steps are disclosed herein,and without intending to publicly dedicate any patentable subjectmatter. All references cited herein are incorporated by reference intheir entirety.

1.-29. (canceled)
 30. A passive electronics component comprising anelectrode layer of electric conducting nanoparticles that are coatedwith a thin film of oxidation-resistant material, wherein said thin filmof oxidation-resistant material prevents oxidation of saidnanoparticles, and wherein a function of said electrode layer issubstantially the same to a similar electrode layer of electricconducting nanoparticles in the absence of said thin film ofoxidation-resistant material.
 31. The passive electronics component ofclaim 30, wherein said thin film of oxidation-resistant materialprovides no significant additional resistivity to said nanoparticles.32. The passive electronics component of claim 30, wherein said thinfilm of oxidation-resistant material does not significantly affect thesintering of said nanoparticles.
 33. The passive electronics componentof claim 30, wherein said thin film of oxidation-resistant materialcomprises a thin film of wide bandgap material.
 34. The passiveelectronics component of claim 33, wherein said thin film of widebandgap material comprises a thin film of a material selected from thegroup consisting of aluminum oxide, hafnium oxide, zirconium oxide,silicon oxide, boron oxide, aluminum nitride, gallium nitride, boronnitride, silicon carbide, boron carbide, or a combination thereof. 35.The passive electronics component of claim 33, wherein the thickness ofsaid thin film of wide bandgap material is 5.5 nm or less.
 36. Thepassive electronics component of claim 30, wherein said thin film ofoxidation-resistant material comprises a thin film of semiconducting orconducting material
 37. The passive electronics component of claim 31,wherein the resistivity of said thin film of oxidation-resistantmaterial is 10,000 mW-cm or less.
 38. The passive electronics componentof claim 30, wherein said thin film of oxidation-resistant materialcomprises a dopant material such that said dopant material increases theconductivity of said thin film of oxidation-resistant material by atleast 100%.
 39. The passive electronics component of claim 30, wherein athermal oxidation onset temperature of said nanoparticles is at least25° C. higher than the same nanoparticles in the absence of said thinfilm of oxidation-resistant material.
 40. The passive electronicscomponent of claim 30, wherein the average particle size of saidnanoparticles is 500 nm or less.
 41. The passive electronics componentof claim 30, wherein said thin film of oxidation-resistant material isproduced at least in part by an atomic layer deposition process.
 42. Thepassive electronics component of claim 30, wherein said passiveelectronics component comprises a plurality of said electrode layers.43. The passive electronics component of claim 30, wherein said passiveelectronics component is selected from the group consisting of aresistor, a capacitor, an inductor, a transformer, an actuator, apiezoelectric, a varistor, a transducer, a memristor, a sensor, athyristor, a thermistor, and a transistor.
 44. A passive electronicscomponent comprising a dielectric or piezoelectric layer ofcorresponding nanoparticles that are coated with a thin film of areliability-improving material.
 45. A passive electronics componentcomprising: a dielectric and/or piezoelectric layer comprising acorresponding nanoparticles; and an electrode layer comprising electricconducting nanoparticles, wherein said nanoparticles of said dielectricand/or piezoelectric layer are coated with a thin film of areliability-improving material and said electric conductingnanoparticles are coated with a thin film of oxidation-resistantmaterial.
 46. An electronic device comprising the passive electronicscomponent of claim
 30. 47. An electronic device comprising the passiveelectronics component of claim
 44. 48. An electronic device comprisingthe passive electronics component of claim 46